Apparatus for determining paraffin percentages



1951 K. A. FISCHER 2,562,901

APPARATUS FOR DETERMINING PARAFF'IN PERCENTAGES Filed May 13, 1948 gyf/ N 5 MlN n- O COLD AIR JET /2 4 JTEAMTRAP 3 T/APHRAGM PHOTOVOLTQ,C CELL 24 COLLECTING LENJ u AMMETEL V VENTOR.

mgr/ li 'fienl Patented Aug. 7, 1951 APPARATUS FOR DETERMINING PARAFFIN PERCENTAGES Karl A. Fischer, Washington, D. 0.

Application May 13, 1948, Serial No. 26,910

4 Claims. (Cl. 88-14) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein, if patented, I

-may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to apparatus for indicating the purity of crystallized material and more particularly to an electro-optical apparatus for determining wax percentages. The need for such determination is specifically applicable in plant processes for producing waxes either of a purified character as by evaporating methods or waxes as they are obtained from dewaxing oils of either a mineral or vegetable character.

Generally, such determinations are made by a technical and careful crystallization of waxes from solvents on the basis of weights and measures. This method of determination usually requires a time element which is not conductive to efficient plant production. Further, it has been found that for different waxes the crystalline formation even if carefully conducted on glass plates may vary due to orientation or other infiuence and thereby cause errors in the determination of parafiinic percentages.

Based on experimental data and careful micro scopic examination it has been found that paraffinic crystals, in contrast to most other crystals, have no tendency to include oil or liquid. However, an oil or liquid may adhere to the outside faces of such crystals or may be contained within capillary spaces in a mass'or body of such crystals. Accordingly, it has been discovered that by a uniform method of crystallization, such oil or liquid retention can be tested and measured on the basis of the color shade caused by the addition of oil or liquid soluble dye stuffs which may be crystallized with the paraifinic substance.

It is, accordingly, an object of this invention to provide an apparatus for electro-optically detcrmining the parafiinic content of uniformly crystallized waxes.

Another object of this invention is to provide apparatus for uniformly crystallizing a contaminated wax film with a crystallizable dye stuff.

A further object of this invention is to provide a simple arrangement'adaptable to easy attachment to a wax producing system for readily .Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings, in which,

Figure 1- is a diagrammatic illustration of apparatus for forming a body of uniformly crystallized wax; and,

Figure 2 is an optical system used with the apparatus disclosed in Figure 1.

Referring to the drawings, a molten wax material I0 is evenly fed, for example, from a wax purifying or dewaxing process (not shown) by conduit ll into vat l2. The conduit II is encased in a steam jacket l3 and the vat I2 is encased in, or surrounded by, a steam jacket l4 fed by conduit l4. These steamjackets l3 and I4 are maintained at suitable temperatures, depending upon the relative melting points of the wax material undergoing testing, to keep the wax flowing through conduit II and in a molten condition in vat l2.

By means of conduit II a dye stuff in the nature of a Sudan dye, as Sudan red, or alizarinirisol blue or the like, readily soluble in mineral oils, vegetable oils and molten paraflin is introduced into conduit II in minute quantities, for example, to form a 0.1 per cent solution in vat l2. A force feed such as an oil injector or similar pumping device may be utilized with conduit II. The coloring agent may be introduced into the liquid flowing in conduit l l by conduit ll either in dry powder form, or dissolved in molten paraflin or oil, as preferred. The minute quantities of added coloring agentand vehicle, if used, do not materially affect the final qualitative results, other than as hereinafter indicated. If necessary, and as expected, the added oil or paraffin vehicle is in known amounts and may be taken into consideration for quantitative determinations. While the illustrated coloring agents are soluble in molten paraffinic material the solidified paraflin or wax excludes the coloring agent, and if no solvent impurity, as oil, is present it reassumes its powder form which is normally in such slight amounts as to be uneffective as to coloring in the final analysis.

Suitable wax overflow or outlet pipe i5 inclosed in steam jacket I6 is provided on vat l2 in order to maintain a proper level and outflow for excessive liquid wax which may be introduced by the conduit l I. Further vat l2 may be provided with an outlet drain (not shown) and the steam jacket [4 is provided with a conventional steam trap outlet l1.

Positioned adjacent the vat I2 is a thin glass disc l8 of approximately 1.0 millimeter thickness mounted on and adapted to be rotated by shaft I8. The shaft I8 is coupled by conventional gearing (not shown) to a suitable motor (not shown) which turns the edge portion of disc I8, at an approximate rate of 1 revolution in minutes 'or more, and permits it to pass through the molten wax l0 enabling the edge portion of disc 18 to pick up a film IQ of approximately 0.1 millimeter thickness (shown in exaggerated form). The edge of disc l8 and film I9, as it moves out of the body of molten wax l0, passes jet 20 through which an air fiow is forced, to cool and crystallize the crystallizable wax and dye contained in film l9. This air fiow may be cooled by obvious means as refrigeration or the like to temperatures which will solidify and crystallize the wax exclusive of its dye content in the film I9.

As heretofore indicated the dye stuff introduced by conduit II is uniformly mixed, for example, by baflles 2| into molten wax l0 and its possible contaminants in which the dye is soluble, and the slowl turning disc picks up a film of wax containing a proportional dye content. The slow movement of disc l8 permits a time interval to lapse between the solidification or crystallizing stage and testing stage, hereinafter described, which establishes color equilibrium in the film l9. This color equilibrium requires a time lapse of five to ten minutes before proper results can be evaluated or .determined as the color shade of dye stufi does not become immediately constant.

Thereby, the dissolved dye content of the wax is found to be in relation to its oil content in that, for example, by use of Sudan red, a wax material containing an excessive quantity of oil will be a bright red color. Waxes containing traces of oil will result in a slight pink color and oil-free waxes show evenly and faintly grey in color. It will, therefore, be apparent that due to the solubility of dye in oil such graduations in color are measurable and such measurements will be indicative of the purity of the wax material.

This measurement or testing of the film I9 is provided for by the use of a light beam from source 22 which may be, for example, a light bulb of low voltage. The light source 22 projects a light beam through the collector lens 23, green color filter 24 and diaphragm 25 onto the crystallized wax body l9, at for example, point 26, the pofieipn of the light beam which passes from the diaphragm 25 and is transmitted through the crystallized wax body I9 is in relation to the dye content and registers on a conventional photovoltaic cell 21.

The action of the photovoltaic cell 21 is in accordance with established principles of producing a current proportional to the light intensity received which is registered by microammeter 28 through conductor wires 29 and 30. The microammeter 28 is scaled in graduations to represent, according to the proportion of light transmitted, the percentage or purity of the molten wax.

As illustrated in the above example, a green filter 24 is used with a wax material containing a red color to produce a complementary effect.

Further, for percentage determinations of low melting soft paraffins which must be examined at relatively low temperatures light my heat blocking means, as a water. cell or the like, may be in-. serted in the path of the light beam before it is transmitted through the film. In the event that the crystallized material has a high melting point an unfiltered white light may be passed to the crystallized film I8.

By the above described apparatus there is disclosed a plant control means which provides easy and read determination of the percentage of wax or parafiinic purity of a wax material as it is produced in a wax purifying system or by the dewaxing of oils as practiced by the trade.

Further, it will be obvious that different plant conditions using or producing different waxes and oils will regulate and operate the apparatus on the basis of conditions and standards suitable to each.

For example, the process as disclosed and described is readily adaptable for qualitative determination in batch processing, as only periodic checks are necessary and the solidified film may be removed from disc l8 by remelting the solid in the molten solution 10 without resolidification until a new reading or determination is to be made. Otherwise, the solidified film may be removed from the disc I 8 by suitable solvents. Normally, inflow of new molten paraflinic material and coloring agent through conduit 2| and outflow of tested material through conduit l5 will provide a change of molten solution in container l2 sufiicient for general qualitative determinations of plant runs.

Having thus described my invention. it will be apparent that this method and apparatus may be utilized to the purposes and advantages above indicated in addition to being applicable for determination of the purity and clarit of crystallizable materials having characteristics equivalent to wax contaminated by solvents or other materials within which a crystallizable dye is soluble.

While the present crystallizing and testing arrangement has been described in considerable detail, it will be obvious that various minor changes may be made within the scope of the appended claims.

Reference is made to my copending application Serial No. 26,914, Method of Testing Wax, filed May 13, 1948.

I claim:

1. Apparatus for measuring the purity of a normally solidified parafllnic body by color modification of the impurities contained therein, comprising a container, liquid feed means and liquid outlet means for said container, liquefying means for maintaining a solidifiableparafiimc body in liquid condition in said container, feed means connected to said liquid feed means for introducing into said liquid body a coloring agent which is soluble in said liquid body and insoluble in the solidified parafilnc component of said body, a transparent disc positioned above said container body and adapted to rotate its edge in the container which edge removes a film of the liquefied .body adhering thereto, conditioning means for solidifying the film adhering to the edge of said disc, light means for measuring the coloring of said impurities by said coloring agent, and time delay means to provide color equilibrium in the solidified film between the initial solidification of the said film and the measuring of the colorme effect.

2. Apparatus for measuring the purity of a normally solidified parafiinic body by color modification of the impurities contained therein, comprising a container, liquid feed means and liquid outlet means for said container, liquefying means for maintaining a solidifiable paraflinic body in liquid condition in said container, feed means connected to said liquid feed means for introducing into said liquid body a coloring agent which is soluble in, said liquid body and insoluble in the solidified parafllnic component of said body, a transparent disc positioned above said container body and adapted to rotate its edge in the container which edge removes a film of the liquefied body adhering thereto, means for rotating said disc at a uniform slow speed, and photoelectric means aligned with the edge of said disc at a point remote from the point of egress of said .disc from the contents of said container for measuring the coloring imparted b said coloring agent to the impurities in the film which solidifies on said disc during its rotation.

3. Apparatus according to claim 2, wherein said photoelectric means include a color filter of a color complementary to that of said coloring agent. v

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 10 Number Name Date 1,895,760 Hunt Jan. 31, 1933 2,195,315 Evelyn Mar. 12, 1940 2,234,697 Hickman Mar. 11, 1941 2,398,435 Marks Apr. 16, 1945 2,445,494 Redmond July 20, 1948 2,489,286 Grant Nov. 29, 1949 

1. APPARATUS FOR MEASURING THE PURITY OF A NORMALLY SOLIDIFIED PARAFFINIC BODY BY COLOR MODIFICATION OF THE IMPURITIES CONTAINED THEREIN, COMPRISING A CONTAINER, LIQUID FEED MEANS AND LIQUID OUTLET MEANS FOR SAID CONTAINER, LIQUEFYING MEANS FOR MAINTAINING A SOLIDIFIABLE PARAFFINIC BODY IN LIQUID CONDITION IN SAID CONTAINER, FEED MEANS CONNECTED TO SAID LIQUID FEED MEANS FOR INTRODUCING INTO SAID LIQUID BODY A COLORING AGENT WHICH IS SOLUBLE IN SAID LIQUID BODY AND INSOLUBLE IN THE SOLIDIFIED PARAFFINIC COMPONENT OF SAID BODY, A TRANSPARENT DISC POSITIONED ABOVE SAID CONTAINER BODY AND ADAPTED TO ROTATE ITS EDGE IN THE CONTAINER WHICH EDGE REMOVES A FILM OF THE LIQUEFIED BODY ADHERING THERETO, CONDITIONING MEANS FOR SOLIDIFYING THE FILM ADHERING TO THE EDGE OF SAID DISC, LIGHT MEANS FOR MEASURING THE COLORING OF SAID IMPURITIES BY SAID COLORING AGENT, AND TIME DELAY MEANS TO PROVIDE COLOR EQUILIBRIUM IN THE SOLIDIFIED FILM BETWEEN THE INITIAL SOLIDIFICATION OF THE SAID FILM AND THE MEASURING OF THE COLORING EFFECT. 